tely to discriminate Mainland Chinese.  This open exhibition obviously is for the purpose to impress as many Hong Kong people as possible.  There are only a limited number of people that can be accommodated during the exibition time.  In order to maximize the effect of impressing  Hong Kong people, of course you want all the visitors to be just bona fide Hong Kong people.  Mainland Chinese people can visit at other place at other time. 

Frankly, probably only the Hong Kong people need more patriotism education, not Mainland Chinese.  To allow only Hong Kong people to visit is actually an unspoken and tacitly discriminative treatment of the Hong Kong people, because they are actually the ones deemed inherently less patriotic than the Mainland Chinese!